Getting the big Work Package 4 pull request ready
for merging and extending it with some fixes (e.g. supporting the new memory layout of unique vecs).

Added support
for debug info about locals declared with destructuring patterns. This works very stably already.

Fixed function argument handling which has been broken for a while now. Unfortunately, there is
still an issue with function argument destructuring. I don’t know really what’s going on here
because the code should essentially be the same as with local variables. This will be the first
thing to look into next week.